Chest pain

What is PACSA?

The NSW pathways for acute coronary syndrome assessment was developed by the ECI and is available below. PACSA replaces the NSW Chest Pain Pathway that was published in 2011. It has been designed to standardise the practice of assessing and managing patients presenting to EDs in metropolitan, regional, and rural/remote areas with suspected acute coronary syndrome (ACS). PACSA is based on the latest evidence relating to cardiac biomarkers and management of chest pain.

• NSW Health PACSA Guideline

What is CT Coronary Angiogram?

CTCA is becoming established as a relatively non-invasive imaging technology for the assessment of coronary arteries, with a high sensitivity for the detection of atherosclerosis. It has been shown to have a high negative predictive value for future cardiac events.

Imaging is performed using an ECG-gated multi-slice CT scanner during a timed bolus of intravenous contrast. Patients often require heart rate control with oral or intravenous beta-blockers, and may be given sublingual GTN for coronary vasodilation. Angiographic images are reconstructed in 3D to visualise coronary stenosis caused by calcified or non-calcified plaque.

Radiation doses typically range from 2mSv to 12 mSv (yearly background radiation dose is 3mSv).

What are the indications for use in ED?

CTCA can be used to further evaluate chest pain in ED patients with low-to-intermediate pre-test probability of coronary artery disease (CAD) with no ECG changes and normal cardiac enzymes.

CTCA is not appropriate for patients with known significant CAD or a high pre-test probability of CAD.

Advantages

• Excellent negative predictive value (but comparable to standard practice using serial ECG and biochemical markers)
• Studies (mainly from USA and not reproduced in Australia) show earlier completion of assessment, shorter length of stay in ED, more direct discharges from ED, and a decreased chance of hospital admission.
• Potentially lower ED costs (although total overall costs are not significantly different).

Disadvantages

• Significant radiation dose
• Contrast load and risk of adverse reactions (anaphylaxis, nephrotoxicity)
• Requires access to CTCA-capable machines and experienced radiologists
• Potentially lead to interventional procedures that may not be justified.
• Estimated 50% of patients excluded due to known CAD or other contraindications.

Evidence so far

Although CTCA is a useful test in the non-emergency setting, current evidence does not support its use in the assessment of Australian ED patients with chest pain.

In ED, CTCA does not convincingly demonstrate superiority over good history, examination, and serial ECG and troponin testing.

1. Foy, A et al. presented a meta-analysis at the 2016 American Heart Association Scientific Symposium.

• CTCA was more likely to lead to invasive coronary angiography (7.7% vs 5.3%) and revascularisation (4.3% vs 2.1%).
• However, there was no difference in the incidence of major adverse cardiac events, repeat presentations, or rehospitalisation.
• In their commentary, they discuss potential harm due to complications of invasive angiogram / angioplasty; overall number needed to harm with CT is about 400-500, compared with stress testing.

2. Prof. Anne-Marie Kelly published a 2013 review of CTCA use in the ED.

3. Weigold WG. Coronary computed tomography angiography in the emergency department: the high stakes game of low risk chest pain. J Am Coll Cardiol. 2013 Feb 26;61(8):893-5.

• Earlier ED discharge and lower overall cost estimates for CTCA group.
• More interventions in CTCA group.

4. Hoffmann, U., Truong, QA., Schoenfeld, DA. et al. Coronary CT angiography versus standard evaluation in acute chest pain. N Engl J Med 2012;367:299–308.

• CTCA improved efficiency of clinical decision making.
• CTCA resulted in increased additional testing and radiation exposure, with no decrease in the overall costs of care.

5. Litt, HI., Gatsonis, C., Snyder, B. et al. CT angiography for safe discharge of patients with possible acute coronary syndromes. N Engl J Med 2012;366:1393–403.

• CTCA allows safe, earlier discharge from ED.

6. Goldstein, JA., Chinnaiyan, KM., Abidov, A. et al. The CT-STAT (Coronary Computed Tomographic Angiography for Systematic Triage of Acute Chest Pain Patients to Treatment) trial. J Am Coll Cardiol 2011;58:1414–22.

• CTCA diagnostic pathway is safe, leads to earlier discharge, and lower overall cost.